Motorshield working -- in only one direction

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keith0603
 
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Motorshield working -- in only one direction

Post by keith0603 »

I just got my Motorshield hooked up to my Arduino Mega 2560 driving 4 motors (4WD Robot from MakerShed).

Using the MotorTest example, and cycling through each of the 4 motors, I found that the motors are only running in one direction. The "reverse" on each motor doesn't produce anything (sound or motion).

P.S. I'm running the motors off EXT PWR @ 7.5v and the Arduino is currently running off USB. Also, I added a single 0.1uf ceramic cap across the motor leads.

Any ideas on where to start to troubleshoot?

Thanks!

Keith

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adafruit_support_bill
 
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Re: Motorshield working -- in only one direction

Post by adafruit_support_bill »

(4WD Robot from MakerShed).
Also, I added a single 0.1uf ceramic cap across the motor leads.
Those motors have a lot of brush noise. For that platform, many people find they need the full 3-cap treatment. (scroll to the bottom of this link) : http://learn.adafruit.com/adafruit-motor-shield/faq

If that doesn't fix it, post photos of the front and back of your shield and we'll see if we can spot the problem.

keith0603
 
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Re: Motorshield working -- in only one direction

Post by keith0603 »

Alrighty. I will give that a shot.

Thanks for the quick reply!

keith0603
 
Posts: 5
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Re: Motorshield working -- in only one direction

Post by keith0603 »

No go. I added the 2 additional caps. Same result. I also hooked it up to an Uno R3 with the same result.

Here are pics of both sides of the board. Any help would be very much appreciated.
2013-03-31 17.30.08.jpg
2013-03-31 17.30.08.jpg (306.9 KiB) Viewed 404 times
2013-03-31 17.29.54.jpg
2013-03-31 17.29.54.jpg (317.29 KiB) Viewed 404 times

keith0603
 
Posts: 5
Joined: Wed Feb 06, 2013 2:05 am

Re: Motorshield working -- in only one direction

Post by keith0603 »

I suppose I could reverse the leads on one set of motors and use one set to drive forward and one set to drive reverse! :D

keith0603
 
Posts: 5
Joined: Wed Feb 06, 2013 2:05 am

Re: Motorshield working -- in only one direction

Post by keith0603 »

Ok. Found the problem. After reading some other posts here, I found someone else that did the same thing as I did. I hooked one lead on the motor to ground (thinking it was common) instead of both leads to each of the two M1 terminals and ignoring GND. I'm assuming GND is used for Stepper motors.

Anyway, back on track. Now, I'm thinking that instead of just acknowledging there is an obstacle ahead of it and proceeding on at full speed, my robot can now reverse and avoid! Life is good. :D

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adafruit_support_bill
 
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Re: Motorshield working -- in only one direction

Post by adafruit_support_bill »

Glad that you figured it out. Your soldering on the shield looks fine. Good luck with your robot! :D

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